Double-blind, randomized, placebo-controlled clinical study of the performance and safety of using a mixture of probiotic strains in the modulation of functional digestive disorders

• Grant number: 24/07166-6
• Support Opportunities: Regular Research Grants
• Start date: September 01, 2025
• End date: August 31, 2027
• Field of knowledge: Health Sciences - Nutrition
• Principal Investigator: Raquel Susana Matos de Miranda Torrinhas
• Grantee: Raquel Susana Matos de Miranda Torrinhas
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Dan Linetzky Waitzberg ; Elizabeth Aparecida Ferraz da Silva Torres ; Geni Rodrigues Sampaio ; Joël Doré ; Philip Charles Calder

Abstract

The intestinal microbiota plays crucial roles in the human body, regulating metabolism and immunological functions. Disturbances in microbial composition, known as dysbiosis, are associated with various pathologies, particularly within the gastrointestinal tract. Probiotics, living organisms capable of enhancing intestinal microbial balance and promoting positive effects on individual health, have demonstrated the ability to alleviate gastrointestinal symptoms through mechanisms that are not yet fully understood. Aim: To evaluate the efficacy and safety of supplementation with a blend of bacterial strains possessing probiotic properties in healthy women experiencing alterations in bowel habits and associated gastrointestinal symptoms. Methods: We aim to recruit 80 non-obese adult women with reported changes in bowel habits for a minimum of three months and recurrent abdominal discomfort. Inclusion criteria require volunteers to be between 18 and 60 years old, with a BMI between 18.5 and 29.9 kg/m², and a diagnosis of constipation or diarrhea according to Rome IV criteria. Exclusion criteria include gastrointestinal diseases, diabetes, prior gastrointestinal surgeries, use of specific medications, and pregnancy. The intervention will involve a 12-week supplementation period with a blend of probiotic strains, including Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus paracasei, and Bifidobacterium lactis (Probiatop®, FQM Brazil), or Placebo (collagen). Follow-up will occur through both in-person and remote visits every 4 weeks. Clinical data, including the characterization of bowel habits, gastrointestinal symptoms, and quality of life, as well as anthropometric measurements and dietary intake, will be recorded. Fecal samples will be collected to analyze gut microbiota composition, microbial metabolites (short-chain fatty acids), and permeability markers (zonulin). Adverse events will be monitored throughout the study. (AU)